The invention refers to a method of monitoring an oil flow in a means for the oil and air lubrication of units or the bearings thereof, in which oil drops are transported by an air flow along a wall of a tube and are thereby expanded in a streak-like manner, wherein fluctuations of the oil flow are detected and a signal that corresponds to the fluctuations is output, and wherein the fluctuations of the oil flow are detected by a streak sensor, which detects a streak shape, streak size, streak frequency and/or streak sequence of the oil flow on the wall of the tube in an opto-electronic manner.
The so-called oil and air lubrication is a rational lubrication method whose use is preferred if a finely metered oil flow shall be supplied in a possibly continuous way to a friction mark. The latter is for instance the case in quickly running rolling bearings as they are used amongst others in spindles of tool machines. The monitoring of the oil flow was formerly the job of the operating personnel by direct inspection (user manual: Schmierungstechnik Zentralschmieranlagen, Willy Vogel AG, 1966, pg. 4.15).
It is clear that the above-mentioned monitoring did not only require the use of transparent pipelines but also a sufficient attention of the respective operator.
A lubricating means is known from DE 44, 39 380 A1, in which oil is released from a flowing film by air flow in small droplet particles and supplied to a lubricating point. An oil atomization is to be avoided. A dynamic measurement of the oil flow rate is possible by a light sensor of the device of DE 44 39 380 A1.
In the device of JP 02 271 197 an oil film is transported on a wall by means of an air flow and it is monitored by infrared sensors.
The object of the invention to provide a method of the type taken into consideration which enables an automatic monitoring of the lubricant supply of a bearing portion with the character of the means taking the oil-air lubrication into consideration.
This object is solved according to the invention in that fluctuations of the oil flow are detected by a streak sensor and that a signal corresponding to the fluctuations is output by the streak sensor.
The method according to the invention utilizes the wavy travel movements of the oil streaks to either influence the lubrication process preferably by detecting the frequency of the crests or hollows of a wave, or to turn off the lubricating unit in the case of an inadequate provision of lubricant or in the case of a failure of the lubricant supply.
The subject matter of the invention is moreover a device for monitoring the oil flow of a means for the oil and air lubrication of components.
The invention will now be described by means of the block diagrams shown in the enclosed drawings.